How to Enable and Select a Shader Pack in Iris

Iris only renders shaders when you explicitly tell it to, so the first step after installing is picking a pack and turning it on.

Opening the Shader Selection Screen

From the main menu, open Options, then Video Settings, and look for the Shader Packs button. You can also reach it from the in-game pause menu. This screen lists every shader pack Iris has detected in your shaderpacks folder, plus an option at the top for Internal (no shaders) and any disabled packs.

Applying a Pack

Click a pack in the list to select it, then click Apply. The world reloads its rendering pipeline and you should immediately see new lighting, shadows, and water. If nothing changes, confirm you did not leave Internal selected. Use the arrow buttons to move packs up or down if you want a different one to load by default.

Toggling Without Uninstalling

To temporarily turn shaders off, select Internal and apply — this keeps your pack installed but disables its effects. This is handy when a pack causes visual glitches in a specific dimension or with certain mods, since you can switch back instantly.